The present invention relates to a pickup lens for an optical disk which is used for reading information from a storage medium, or recording, mainly by using a laser beam, and in particular, to a pickup lens for an extremely small optical disk.
There are various formats (specifications) for information recording media available on the market, and various technologies are employed and studied for the various formats.
In recent years, in particular, a broadband has become popular to create a broadband age, and there are circulating high-volume contents of images, animations and sounds. It is therefore necessary, even for general users, to stock high-volume data.
With respect to a recording medium for data stocking, original ones were those wherein audio cassette tapes were used, and FD (floppy disk) is still used even today. In recent years, Zip (high-volume floppy disk having the measure of capacity of 100 M-200 M), MO (photo-electro-magnetic disk having the measure of capacity of 640 M-2.3 G), CD (optical disk having the measure of capacity of 640-700 M) and DVD (optical disk having the measure of capacity of 4.7 G) are used, which shows that the measure of capacity has grown great.
Among the aforesaid recording media, those utilizing light have their own optical systems.
The optical disks mentioned above have started from the music CD, and therefore, it is always necessary for the DVD which is becoming a leading recording medium now to consider interchangeability with CD, and a size of the DVD is large, which makes it difficult to provide a small-sized equipment, resulting in a problem. To solve this problem, a small-sized medium in a size of 8 cm and a deformed medium having a size of a business card have made an appearance, but it is unavoidable that they have less capacity.
Further, the DVD has a problem that many standards concerning information recording are present and interchangeability between them is insufficient.
With respect to the photo-electro-magnetic disk, problems of interchangeability with standards for low volume and problems that a size of a medium restricts a size of equipment remain unchanged, although the measure of capacity has been made great.
For those problems, there has been proposed a standard concerning a small-sized recording medium which is quite novel.
However, when a medium is small in size, an optical pickup lens and a unit are required to be small in size.
When an optical pickup lens and a unit are made to be small in size, manufacturing, assembling and adjustment of the lens itself become extremely difficult.
An object of the invention, therefore, is to propose forms which make manufacturing, assembling and adjustment to be easy for an optical pickup lens and an optical pickup unit which are extremely small.
The above object can be attained by the following structures and methods in respective Item.
Item (1-1)
An objective lens used in an optical pickup device that conducts recording and/or reproduction of information for an optical information recording medium, wherein there are provided a lens section which includes a flange section and is almost in a circular form, and a connecting section used as a supporting section for the lens section, the connecting section is provided to be solid with the lens section, and each of them satisfies the following relations;
0.5xe2x89xa6Axe2x89xa62.0
0.3Axe2x89xa6Bxe2x89xa61.7A
where A represents a diameter (mm) of the lens section viewed in the optical axis direction, and B represents a width (mm) of the connecting section viewed in the optical axis direction.
Item (1-2)
The objective lens according to Item (1-1), wherein a connecting section is provided to be extended from the lens section.
Item (1-3)
The objective lens according to Item (1-2), wherein the objective lens is formed by filling resins through a single inlet in a metal mold.
Item (1-4)
The objective lens described in Item (1-2) or in Item (1-3), wherein the following expression is satisfied.
0.3Axe2x89xa6Bxe2x89xa60.8A
Item (1-5)
The objective lens described in Items (1-2)-(1-4), wherein the connecting section is cut so that nothing may be protruded outside a shape which is roughly circular when viewed in the direction of an optical axis.
Item (1-6)
The objective lens according to Item (1-1), wherein two connecting sections are provided to be extended from the lens section in the direction to face each other.
Item (1-7)
The objective lens according to Item (1-6), wherein the two connecting sections are different from each other.
Item (1-8)
The objective lens according to Item (1-7), wherein the two connecting sections are different from each other in terms of thickness in the optical axis direction.
Item (1-9)
The objective lens according to Item (1-6)-Item (1-8), wherein the two connecting sections are different from each other in terms of thickness in the direction perpendicular to the optical axis.
Item (1-10)
The objective lens according to Item (1-6)-Item (1-9), wherein the two connecting sections are different from each other in terms of a length of the width viewed in the direction of the optical axis.
Item (1-11)
The objective lens according to Item (1-1), wherein a lens section is formed to be arranged at the center of a rectangular connecting section.
Item (1-12)
The objective lens according to Item (1-6)-Item (1-11), wherein the objective lens is formed by filling resins through a single or plural inlets in a metal mold.
Item (1-13)
The objective lens according to Item (1-6)-Item (1-10) or to Item (1-12), wherein two connecting sections are provided to be extended from the lens section in the direction to face each other, and are formed with resins filled through an edge portion of each connecting section.
Item (1-14)
The objective lens according to Item (1-11) or Item (1-12), wherein a lens section is formed to be arranged at the center of a rectangular connecting section, and resins are filled through an edge portion of the connecting section to be formed.
Item (1-15)
The objective lens according to Item (1-12)-Item (1-14), wherein a weld is located outside an optical functional surface of the lens section.
Item (1-16)
The objective lens according to Item (1-1)-Item (1-15), wherein the objective lens is an aspherical lens.
Item (1-17)
The objective lens according to Item (1-1)-Item (1-16), wherein the objective lens is a lens obtained through compression molding.
Item (1-18)
The objective lens according to Item (1-1)-Item (1-16), wherein the objective lens is a lens obtained through injection molding.
Item (1-19)
The objective lens according to Item (1-18), wherein the connecting section serves also as a resin inflow path for the lens section.
Item (1-20)
The objective lens according to Item (1-18)-Item (1-19), wherein the objective lens is a plastic lens.
Item (1-21)
The objective lens according to Item (1-17), wherein the objective lens is a glass lens.
Item (1-22)
The objective lens according to Item (1-1)-Item (1-21), wherein a diffractive Item is formed on the optical functional surface of the objective lens.
Item (1-23)
A manufacturing method for an optical element for forming by filling resins through a plurality of inlets in a metal mold, wherein the time to start injecting resins is staggered when filling resins through the plural inlets.
Inventions relating to a handling method among the present inventions are attained by the following Items.
Item (2-1)
An optical molded component having therein a supporting shaft section having a first cross-sectional area, a connecting section that is provided to be continued in the axial direction of the supporting shaft section and has a cross-sectional area smaller than the first cross-sectional area and an optical functional section provided to be continued from the connecting section, wherein the total weight of the supporting shaft section and the connecting section is greater than the weight of the optical functional section.
Item (2-2)
An optical molded component having therein a supporting shaft section having a first cross-sectional area, a connecting section that is provided to be continued in the axial direction of the supporting shaft section and has a cross-sectional area smaller than the first cross-sectional area and an optical functional section provided to be continued from the connecting section, wherein the total weight of the supporting shaft section and the connecting section is not less than 70% of the whole weight.
Item (2-3)
An optical molded component having therein a supporting shaft section having a first cross-sectional area, a connecting section that is provided to be continued in the axial direction of the supporting shaft section and has a cross-sectional area smaller than the first cross-sectional area and an optical functional section provided to be continued from the connecting section, wherein an information recording site is provided on the supporting shaft section.
Item (2-4)
An optical molded component having therein a supporting shaft section having a first cross-sectional area, a connecting section that is provided to be continued in the axial direction of the supporting shaft section and has a cross-sectional area smaller than the first cross-sectional area and an optical functional section provided to be continued from the connecting section, wherein an information recording site is provided on the connecting section.
Item (2-5)
The optical molded component described in Item (2-1)-Item (2-4), wherein a shape of a section of the supporting shaft section is almost circular.
Item (2-6)
The optical molded component described in Item (2-1)-Item (2-5), wherein a shape of a section of the supporting shaft section is almost trapezoid.
Item (2-7)
The optical molded component described in Item (2-1)-Item (2-6), wherein a shape of a section of the supporting shaft section is almost semicircular.
Item (2-8)
In the invention described in Item (2-8), it is characterized that a parallel flat portion that is almost in parallel with a chord section is formed on a part of an arc section of the supporting section in the optical molded component described in Item (2-7).
Item (2-9)
In the invention described in Item (2-9), it is characterized that a protruded portion that is protruded from the parallel flat portion stated above and is in a shape which is almost a truncated square pyramid is formed in the optical molded component described in Item (2-8).
Item (2-10)
In the invention described in Item (2-10), it is characterized that a side section of the protruded portion is composed of a pair of longitudinal sides which face each other in the longitudinal direction of the supporting section and a pair of lateral sides which face each other in the lateral direction, and an angle formed between the longitudinal side and the parallel flat section is made to be 45xc2x0 or less, in the optical molded component described in Item (2-9).
Item (2-11)
The optical molded component described in Item (2-7) to Item (2-10), wherein a normal line on a chord section of the approximate semicircle almost agrees with an optical axis on an optical functional surface of the optical functional section.
Item (2-12)
The optical molded component described in Item (2-1)-Item (2-11), wherein a protruded portion is formed on the supporting shaft section.
Item (2-13)
In the invention described in Item (2-13), it is characterized that the protruded portion is formed to be almost in a truncated square pyramid, in the optical molded component described in Item (2-12).
Item (2-14)
In the invention described in Item (2-14), it is characterized that a corner section of the convex portion is chamfered, in the optical molded component described in Item (2-13).
Item (2-15)
The optical molded component described in Item (2-1)-Item (2-14), wherein a concave portion is formed on the supporting shaft section.
Item (2-16)
The optical molded component described in Item (2-1)-Item (2-15), wherein a stress-concentration portion is formed on the connecting section.
Item (2-17)
The optical molded component described in Item (2-16), wherein the stress-concentration portion is a V-shaped concave portion which is concave in the direction which is mostly perpendicular to the optical axis on the optical functional surface of the optical functional section.
Item (2-18)
The optical molded component described in Item (2-16), wherein the stress-concentration portion is a V-shaped concave portion which is concave in the direction which is mostly the same as the optical axis on the optical functional surface of the optical functional section.
Item (2-19)
In the invention described in Item (2-19), it is characterized that the connecting section has an index portion that is based on a distance from the center of an optical axis of the optical functional section, in the optical molded component described in either one of Items (2-1)-(2-18).
Item (2-20)
In the invention described in Item (2-20), it is characterized that the index portion is formed by cutting into the connecting section, in the optical molded component described in Item (2-19).
Item (2-21)
In the invention described in Item (2-21), it is characterized that the index portion is formed to be protruded from the connecting section, in the optical molded component described in Item (2-19).
Item (2-22)
In the invention described in Item (2-22), it is characterized that the index portion is formed to be a straight line extending in the lateral direction of the connecting section, in the optical molded component described in either one of Items (2-19)-(2-21).
Item (2-23)
In the invention described in Item (2-23), it is characterized that the index portion is formed to be a locus of a circle having a prescribed radius whose center is on the optical axis in the optical molded component described in either one of Items (2-19)-(2-21).
Item (2-24)
When handling the optical molded component described in Item (2-19 to (2-23), a method of handling an molded optical component is characterized in that an optical molded component is taken out of a metal mold for molding an optical molded component that is provided with a first resin inflow path having a first cross-sectional area, a second resin inflow path being located ahead of the first resin inflow path in the direction of resin flow and having a cross-sectional area smaller than the first cross-sectional area and an optical functional section molding section being located further ahead of the second resin inflow path in the direction of resin flow, and then, the optical molded component is handled on the basis of a site formed by the first resin inflow path.
Item (2-25)
When handling the optical molded component described in Item (2-19 to (2-23), a method of handling an molded optical component is characterized in that an optical molded component is taken out of a metal mold for molding an optical molded component that is provided with a first resin inflow path having a first cross-sectional area, a second resin inflow path being located ahead of the first resin inflow path in the direction of resin flow and having a cross-sectional area smaller than the first cross-sectional area and an optical functional section molding section being located further ahead of the second resin inflow path in the direction of resin flow, and then, the optical molded component is handled on the basis of a site which is formed by the first resin inflow path and is continued to a site formed by the second resin inflow path, after the site formed by the first resin inflow path is cut.
Item (2-26)
When handling the optical molded component described in Item (2-19 to (2-23), a method of handling an molded optical component is characterized in that an optical molded component is taken out of a metal mold for molding an optical molded component that is provided with a first resin inflow path having a first cross-sectional area, a second resin inflow path being located ahead of the first resin inflow path in the direction of resin flow and having a cross-sectional area smaller than the first cross-sectional area and an optical functional section molding section being located further ahead of the second resin inflow path in the direction of resin flow, and then, the optical molded component is handled on the basis of a site which is formed by the first resin inflow path and is continued to a site formed by the second resin inflow path, after the prescribed site formed by the first resin inflow path is cut.
Item (2-27)
The method of handling an optical molded component described in Item (2-26), wherein the aforementioned prescribed site is a site formed by the first resin inflow path mentioned above that is away, by a distance determined in advance, from a boundary between the site formed by the first resin inflow path and the site formed by the second resin inflow path.
Item (2-28)
The method of handling an optical molded component described in Item (2-24)-Item (2-27), wherein xe2x80x9chandlingxe2x80x9d means positioning of the optical molded component.
Item (2-29)
The method of handling an optical molded component described in Item (2-24)-Item (2-28), wherein xe2x80x9chandlingxe2x80x9d means holding of the optical molded component.
Item (2-30)
The method of handling an optical molded component described in Item (2-24)-Item (2-29), wherein xe2x80x9chandlingxe2x80x9d means mounting of the optical molded component.
Item (2-31)
The method of handling an optical molded component described in Item (2-24)-Item (2-30), wherein xe2x80x9chandlingxe2x80x9d means cutting of the optical molded component.
Item (2-32)
The method of handling an optical molded component described in Item (2-24)-Item (2-31), wherein xe2x80x9chandlingxe2x80x9d means cutting of the site formed by the second resin inflow path after combining the optical functional section of the optical molded component with another member.
Item (2-33)
The method of handling an optical molded component described in Item (2-32), wherein another member stated above is a cartridge for conveyance.
Item (2-34)
The method of handling an optical molded component described in Item (2-32), wherein another member stated above is a pickup unit.
Item (2-35)
The method of handling an optical molded component described in Item (2-24)-Item (2-34), wherein xe2x80x9chandlingxe2x80x9d means recording information on the site formed by the first resin inflow path.
Item (2-36)
In the invention described in Item (2-36), it is characterized that the xe2x80x9chandlingxe2x80x9d is to record information on a portion formed by the second resin inflow path in the optical molded component, in the method of handling an optical molded component described in either one of Item (2-24)-(2-34).
Item (2-37)
The method of handling an optical molded component described in Item (2-35) or (2-36), wherein the information means a number of a metal mold.
Item (2-38)
The method of handling an optical molded component described in Item (2-35)-Item (2-37), wherein the information means a cavity number.
Item (2-39)
The method of handling an optical molded component described in Item (2-35)-Item (2-38), wherein the recording of information is conducted by marking.
Item (2-40)
The method of handling an optical molded component described in Item (2-35)-Item (2-39), wherein the recording of information is conducted by printing.
Item (2-41)
The method of handling an optical molded component described in Item (2-35)-Item (2-40), wherein the recording of information is conducted by pasting.
The invention of the handling method relating to the molded component among the present inventions can be attained by the following means.
Item (2-42)
The method of handling an optical molded component described in Item (2-12)-Item (2-15), wherein the protruded portion and/or the concave portion is used as an index for positioning.
Item (2-43)
The method of handling an optical molded component described in Item (2-12)-Item (2-15), wherein the protruded portion and/or the concave portion is used as a guide in the course of handling.
Item (2-44)
A metal mold for molding an optical molded component described in any one of Items (2-1) to (2-23), having therein a first resin inflow path having a first cross-sectional area, a second resin inflow path being located ahead of the first resin inflow path in the direction of resin flow and having a cross-sectional area smaller than the first cross-sectional area and an optical functional section molding section being located further ahead of the second resin inflow path in the direction of resin flow, wherein there is formed an optical molded component having therein a supporting shaft section formed by the first resin inflow path, a connecting section formed by the second resin inflow path and an optical functional section formed by the optical functional section molding section.
Item (2-45)
The metal mold for molding an optical molded component described in Item (2-44), wherein a part of the first resin inflow path is formed so that a three-dimensional distinguishing mark may be formed.
Item (2-46)
The metal mold for molding an optical molded component described in Item (2-44)-Item (2-45), wherein the direction of resin flow for each of the first resin inflow path and the second resin inflow path is almost linear.
Item (2-47)
The metal mold for molding an optical molded component described in Item (2-44)-Item (2-46), wherein the direction of resin flow for the first resin inflow path and that for the second resin inflow path are in accord with each other, and are mostly linear.
Item (2-48)
The metal mold for molding an optical molded component described in Item (2-44)-Item (2-47), wherein the direction of resin flow for the first resin inflow path and that for the second resin inflow path are in the relationship to cross mostly at right angles.
Item (2-49)
The metal mold for molding an optical molded component described in Item (2-44)-Item (2-48), wherein the first resin inflow path is a runner.
Item (2-50)
The metal mold for molding an optical molded component described in Item (2-44)-Item (2-49), wherein the second resin inflow path is a gate.
Item (2-51)
The metal mold for molding an optical molded component described in Item (2-44)-Item (2-50), wherein the first resin inflow path is formed so that a shape of a section of the supporting shaft section may be almost circular.
Item (2-52)
The metal mold for molding an optical molded component described in Item (2-44)-Item (2-50), wherein the first resin inflow path is formed so that a shape of a section of the supporting shaft section may be almost trapezoid.
Item (2-53)
The metal mold for molding an optical molded component described in Item (2-44)-Item (2-50), wherein the first resin inflow path is formed so that a shape of a section of the supporting shaft section may be almost semicircular.
Item (2-54)
The metal mold for molding an optical molded component described in Item (2-53), wherein the first resin inflow path and the optical functional section molding section are formed so that a normal line on a chord section of the approximate semicircle may almost agree with an optical axis on an optical functional surface of the optical functional section.
Item (2-55)
The metal mold for molding an optical molded component described in Item (2-44)-Item (2-54), wherein the first resin inflow path is formed so that a protruded portion may be formed on the supporting shaft section.
Item (2-56)
The metal mold for molding an optical molded component described in Item (2-44)-Item (2-55), wherein the first resin inflow path is formed so that a concave portion may be formed on the supporting shaft section.
Item (2-57)
The metal mold for molding an optical molded component described in Item (2-44)-Item (2-56), wherein the second resin inflow path is formed so that a stress-concentration portion may be formed on the connecting section.
The invention relating to the method of molding employing a metal mold among the present inventions can be attained by the following means.
Item (2-58)
An optical molded component that is molded by the metal mold for molding an optical molded component in the aforesaid Items (2-44)-(2-57), and has a supporting shaft section formed by the first resin inflow path, a connecting section formed by the second resin inflow path and the optical functional section formed by the optical functional section molding section.
The invention relating to the method of molding employing a metal mold among the present inventions can be attained by the following means.
Item (2-59)
A method of molding an optical molding component that molds an optical molded component by the use of the metal mold for molding an optical molded component in the aforesaid Items (2-44)-(2-57).
Item (2-60)
In the invention described in Item (2-60), it is characterized that the optical molded component described in either one of Items (2-1)-(2-23) is provided in the optical pickup unit.
The invention relating to a method of assembling an optical pickup unit among the present inventions can be attained by the following means.
Item (2-61)
An optical pickup unit assembling method for the optical pickup unit described in Item (2-60) wherein a molded component in which an optical functional section and a supporting shaft section that is greater than the optical functional section are formed integrally through a connecting section is incorporated with an optical pickup unit through the optical functional section while holding the supporting shaft section, and then, the connecting section is cut.
Item (2-62)
An optical pickup unit assembling method for the optical pickup unit described in Item (2-60) wherein a molded component in which an optical functional section and a supporting shaft section that is greater than the optical functional section are formed integrally through a connecting section is incorporated with a housing container through the optical functional section while holding the supporting shaft section, and then, the connecting section is cut.
Item (2-63)
The optical pickup unit assembling method described in Item (2-61)-Item (2-62), wherein the supporting shaft portion is greater than the optical functional section in terms of volume.
Item (2-64)
The optical pickup unit assembling method described in Item (2-61)-Item (2-63), wherein the supporting shaft portion is greater than the optical functional section in terms of weight.